Mutual Wills and the Constructive Trust UK: Re Goodchild, Re Dale and the Binding Survivor

Updated 31 May 2026 · 9 min read · Wills & Trust Law

Many couples assume that making mirror wills prevents the survivor from changing their will after the first death. They are wrong. Only mutual wills — made under a binding agreement not to revoke — create a constructive trust that locks in the estate plan after the first death. Understanding the difference can prevent costly disputes.

Mirror Wills vs Mutual Wills: The Critical Distinction

Mirror wills are two wills with matching terms — typically each spouse leaving everything to the other, then equally to the children. They are independent legal documents. Either party can revoke or change their mirror will at any time without breaching any legal obligation. There is no contract and no constructive trust.

Mutual wills go further: they are made under a binding agreement that neither party will revoke their will (or alter it in a material way) after the first death. That agreement is the trigger. When the first testator dies, equity steps in and fastens a constructive trust onto the survivor’s estate — preventing them from making testamentary dispositions inconsistent with the agreed scheme.

The Legal Basis: Re Dale and Re Goodchild

Re Dale [1994] Ch 31

Morritt J established the modern framework. A husband and wife made mutual wills in identical terms. After the husband died, the wife made a new will under which most of the estate passed to their son rather than to both children equally. The daughter successfully claimed the benefit of the constructive trust. Morritt J confirmed:

• The constructive trust arises on the first death — not on execution of the wills or on the survivor’s death.
• From the moment of the first death the trust is irrevocable and binds whatever the survivor does subsequently.
• The survivor holds the property on a floating trust during their lifetime, crystallising onto the remaining estate at death.
• The doctrine applies whether the agreement was express or clearly evidenced by conduct and surrounding circumstances.

Re Goodchild [1997] 1 WLR 1216 (CA)

The Court of Appeal confirmed that making mirror wills — even on the same day with the same solicitor — does not by itself establish a mutual wills agreement. There must be a positive express agreement that neither party will revoke their will after the first death. A “common intention” or an expectation is not enough. The court also confirmed that the survivor may freely deal with property during their lifetime; the floating trust only catches what remains in the estate at the survivor’s death.

In Goodchild itself, the claim failed because the evidence did not establish a sufficiently clear contractual agreement — despite the couple’s obvious intention to benefit their son in equal shares.

How the Constructive Trust Operates

Once established, the constructive trust operates as follows:

• Floating trust during survivor’s lifetime: The survivor may use, spend, and enjoy the property (income and capital) for their own needs. The trust does not prevent this. It is sometimes described as a “super-imposed” trust that floats over the estate.
• Crystallisation at death: When the survivor dies, the trust crystallises onto whatever property remains in their estate that was subject to the agreement. The executor of the survivor’s estate holds those assets as constructive trustee for the agreed ultimate beneficiaries.
• Priority over later wills: Any later will by the survivor is formally valid but cannot defeat the constructive trust. The ultimate beneficiaries can sue the survivor’s executor in equity to enforce the trust.
• Uncertainty on lifetime gifts: Whether the trust catches assets acquired after the first death (and not received under the first will) or is limited to assets received under the first will remains unsettled and is determined case by case.

What Evidence Establishes the Agreement?

The burden falls on the party asserting the mutual wills agreement to prove a binding contractual commitment. Evidence courts have accepted includes:

• An express recital in the wills themselves: “We agree that these wills shall not be revoked or altered without the consent of the other.”
• A separate written agreement or memorandum signed by both parties.
• A solicitor’s attendance note recording a clear oral agreement at the time of instruction.
• Consistent conduct and declarations over a long period consistent only with a contractual arrangement (rare — courts are cautious).

What courts have rejected: the mere simultaneous making of mirror wills; common intention without contractual commitment; expectation or assumption without agreement; posthumous statements by the survivor alone.

Why Mutual Wills Are Rarely the Right Answer

Despite their appeal to couples who want to ensure assets ultimately reach their children, mutual wills create inflexibility that causes more problems than they solve:

• Circumstances change — a beneficiary may die, go bankrupt, become estranged, or need to be excluded for welfare reasons. The survivor is locked in.
• Tax law changes — a fixed scheme may become tax-inefficient without the ability to update.
• The scope of the trust is uncertain — litigation over what assets are caught is common and expensive.
• IHT consequences — the constructive trust may produce unintended IHT outcomes, particularly where assets that the survivor would have redirected to the spouse now pass to children without the spouse exemption.

For most couples, a life interest trust (giving the survivor income and occupation rights, with the remainder passing to children) achieves the protective objective with full flexibility for the trustees to adapt to changing circumstances. Mutual wills should only be used with specific legal advice and a clear understanding of the binding nature of the commitment.

FAQs